Keep the vang, convert the main to traditional reefing (and install blocks at the end so you can reef it quickly from the mast, or, even more lazily, from the cockpit if you have pulled down all lines).

On my previous boat, a Havsfidra from 1974, the boom could be rolled with a winch handle, and the attachment for the vang was an enforced hole shaped as a keyhole under the boom. It was surely the best compromise possible, as you could use the vang but only when not reefed, and you could relatively easily reef even in hard wind. However, the sail shape gets lousy, so I bought a new sail with full length battens, and installed 2 reefs, with quick-reefing blocks on the boom. One thousand per cent better.

On my present boat you roll reef by pulling the boom out and twisting it in 90 degree increments. Idiotic. I tried it once and it took WAY too long to take in a reef, plus as usual the shape of the sail gets too baggy, so you end up getting too much healing and too little sailing. In other words, it doesn't contribute to increasing the feeling of having the boat under control in hard wind. I will install the same kind of reefing on this boat ASAP, and a vang, since it is rather important if you ever want to sail down wind...

PS. I seem to recall back in the days that they tried to place some conical shaped filler so that the curve in the bottom of the main would be decreased when rolled up on the boom, but I guess it didn't solve the problem, because the system seems abandoned now. Or maybe it was the rolling mast that killed it. But really, traditional reefing as on modern racers is surely the best. Lines and blocks only.